Phenotyping of industrial hemp (Cannabis sativa) genotypes with different growth habits.

Industrial hemp (Cannabis sativa ) has gained renewed scientific and agricultural interest worldwide as a multi-use, high-value crop, with products spanning textile, clothing, medicinal, food, and construction industries. Cannabis exhibits broad genetic diversity and high phenotypic plasticity, with strong genotype × environment interactions, resulting in varied aboveground growth habits from tall and thin to short and bushy. Here, we compared the growth and response to water deficit over time in seedlings of two tall, thin French dual-purpose industrial hemp genotypes, Felina 32 and Ferimon 12, and one short, bushy Chinese dual-purpose genotype, Han NE, using state-of-the-art non-destructive phenotyping and automated gravimetric watering systems. Despite the different growth habits, growth patterns were remarkably similar. Water deficit consistently reduced shoot and root dry weight, plant height, number of leaf pairs, CO2 assimilation, and stomatal conductance in all three genotypes. Han NE showed potential for greater water use efficiency, possibly linked to the shorter bushy growth habit, but further research is needed to evaluate varying growth habits within different environments and over the entire plant lifecycle. This study provides valuable insights into diverse hemp genotypes to inform field-based agronomic decisions and targeted breeding programs.